Don't empty db by default; don't add players to either entity scan; don't persist entities apart from the player; only one player
Spawn new worlds from new top-level object. Detect current world to make world object active and to make entities active.
top object preloads world objects.
check isVisibleRemote before http.push/poll
tidy up some logging stuff
Don't persist Notify and Observe, because you may not be persisting those objects
testing, bugfix, change tutorial